# std::chrono::year_month_weekday_last::operator+=, std::chrono::year_month_weekday_last::operator-=

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< cpp‎ | chrono‎ | year month weekday last

constexpr std::chrono::year_month_weekday_last& operator+=( const std::chrono::years& dy ) const noexcept; | (1) | (since C++20)
constexpr std::chrono::year_month_weekday_last& operator+=( const std::chrono::months& dm ) const noexcept; | (2) | (since C++20)
constexpr std::chrono::year_month_weekday_last& operator-=( const std::chrono::years& dy ) const noexcept; | (3) | (since C++20)
constexpr std::chrono::year_month_weekday_last& operator-=( const std::chrono::months& dm ) const noexcept; | (4) | (since C++20)

Modifies the time point *this represents by the duration dy or dm.

1) Equivalent to *this = *this + dy;.
2) Equivalent to *this = *this + dm;.
3) Equivalent to *this = *this - dy;.
4) Equivalent to *this = *this - dm;.

For durations that are convertible to both std::chrono::years and std::chrono::months, the `years` overloads (1,3) are preferred if the call would otherwise be ambiguous.

### Example

Run this code

    #include <chrono>
    #include <iostream>
    using namespace std::chrono;

    int main()
    {
        auto ymwdl{August/Friday[last]/2022};
        std::cout << year_month_day{ymwdl} << '\n';
        ymwdl += months(2);
        std::cout << year_month_day{ymwdl} << '\n';
        ymwdl -= years(1);
        std::cout << year_month_day{ymwdl} << '\n';
    }

Output:

    2022-08-26
    2022-10-28
    2021-10-29

### See also

operator+operator- (C++20) | adds or subtracts a `year_month_weekday_last` and some number of years or months (function)

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